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Heterostructure Transistors
Published in M S Shur, R A Suris, Compound Semiconductors 1996, 2020
The noise parameters of both devices were measured using an automated Cascade on-wafer noise parameter measurement system over the 2 to 18 GHz frequency range. The uncertainty in the minimum noise figure measurement is 0.05 dB at 10 GHz and 0.1 dB at 18 GHz. The minimum noise figure and associated gain at 10 GHz as a function of drain current at 300K of a typical ion implanted GaAs MESFET and GaAs p-HEMT are shown in Figure 1.. These measured results show a typical minimum noise figure of 0.85 dB with an associated gain of 11.5 dB occurring at 13.5 mA (or 45 mA/mm) for both the MESFET and p-HEMT. The noise figures and associated gains at 10 GHz are practically identical over the same Ids (bias) range.
Motivation Behind High Electron Mobility Transistors
Published in D. Nirmal, J. Ajayan, Handbook for III-V High Electron Mobility Transistor Technologies, 2019
A perspective view for an n-channel MOSFET is shown in Figure 1.7. Although it looks similar to a MESFET, there are four major differences: (1) the source and drain of a MOSFET are rectifying p–n junctions instead of ohmic contacts; (2) the gate is a metal-oxide-semiconductor structure, meaning that there is an insulator—silicon dioxide (SiO2)—sandwiched between the metal electrode and the semiconductor substrate, while for the MESFET the gate electrode forms a metal-semiconductor contact; (3) the left edge of the gate electrode must be aligned or overlapped with the source contact to facilitate device operation, while in a MESFET there is no overlapping of gate and source contact; and (4) the MOSFET is a four-terminal device, so that there is a fourth substrate contact in addition to the source, drain, and gate electrode, as in the case of a MESFET.
Using CMOS-Compatible SOI MESFETs for Power Supply Management
Published in John D. Cressler, H. Alan Mantooth, Extreme Environment Electronics, 2017
William Lepkowski, Seth J. Wilk, Mohammad Rez Ghajar, Keith Hobert, Bertan Bakkaloglu, Trevor J. Thornton
The MESFET features an fT > 20 GHz and a fmax > 25 GHz [9], which enables it to be switched at high frequencies in excess of 10 MHz with very fast rise and fall times given a proper package and board design. Here it was demonstrated at 500 kHz with 10 ns rise and fall times (Figure 63.11). Significant ringing was observed on the falling side of VDS and the rising side of the gate voltage. Presumably, that can be attributed in large part to the bond wires, which were 3–5 mm long, the stray parasitic inductance from the nonoptimized board design and high-resistance voltage probes used for measurement. The ringing was further exacerbated with a 1 A load and 10 ns rise and fall times. In any case, the ringing was not a result of the MESFET switching transistor, but it does show the MESFET’s ability to withstand larger voltage swings than the CMOS devices on the same 150 nm process. Lastly, the MESFET switching transistor was measured in the presence of radiation up to 300 krad(Si) TID (refer to Figure 23.11 to see a Gummel plot of the irradiated MESFET). From Figure 63.12 it can been that the radiation after 300 krad(Si) TID had a negligible effect on the MESFET’s switching capability. Similar results were seen when measuring from −196° to +150°C. Again, since the Ron only changed slightly across temperature, the MESFET was able to still switch to similar voltage levels. However, the gate leakage did grow as the temperature and radiation dose increased.
A novel SOI MESFET to spread the potential contours towards the drain
Published in International Journal of Electronics, 2020
Mohaddeseh Mohtaram, Ali Asghar Orouji
Unlike Bipolar transistors (BJTs), Field Effect Transistors (FETs) are unipolar devices. It means, there is only one type of carrier, electron or hole, participate in the current of the channel, which makes it possible to exhibit high frequency and low noise behaviour. Among field effect transistors, Metal Semiconductor FETs (MESFET) have large applications in amplifiers, mixers, and oscillators. These devices are a voltage controlled component. In fact, a variable electric field controls the current of the source to the drain with changing the voltage applied to the gate. So far, various efforts have been made to improve the frequency and DC characteristics of MESFET transistors (Braga & Hiu Yung Wong, 2017; Dutta, 2016; Jia et al., 2015; Jia, Hu, & Zhu, 2018; Jia, Yang, & Zhang, 2013; Jia, Zhang, Xing, Luo, & Duan, 2015; Jia, Zhang, Xing, & Ma, 2015; Lakhdar & Lakehal, 2017; Mohtaram & Orouji, 2018)
A theoretical study on the temperature-dependent RF performance of a SiC MESFET
Published in International Journal of Electronics, 2018
In conclusion, we have demonstrated the impact of ambient temperature variation of a SiC MESFET on its electrical characteristics considering two-region model. The performance of the device in terms of drain current, drain resistance and mutual conductance is observed to be degraded at elevated thermal environment. The study has been extended to observe the temperature effect on the cut-off and maximum operating frequency of the device. The frequency performance of the device also degrades significantly as the device temperature gets higher. In addition to this, the self-heating effect of the device is considered in our study and the results are presented. We have also compared our calculated results with experimentally measured cut-off and maximum operating frequency reported in earlier work. The theoretically calculated maximum operating frequency and cut-off frequency of a MESFET are 21.32 and 7.61 GHz, respectively, which are very close to their experimentally reported value 26.2 and 9.1 GHz, respectively.
A novel 4H-SiC MESFET by lateral insulator region to improve the DC and RF characteristics
Published in International Journal of Electronics, 2018
Zohreh Roustaie, Ali A. Orouji
Today, the electronics affects all parts of our lives. Much progress in the electronics and its use in areas such as industry, education, medical, etc. are making progress in these areas. The metal–semiconductor field-effect transistor (MESFET) is a good electronic device. This transistor has a Schottky contact with the gate and is quicker than a metal–oxide–semiconductor field-effect transistor (MOSFET). Also, the MESFET is more suitable than the MOSFET for high power and high frequency applications. The Schottky contact in the MESFET led to the creation of differences between the MESFET and the MOSFET. One important difference is how the channel is formed in both the devices. In the MOSFET, the channel is formed at the interface of the oxide and the silicon. Because carriers in a MOSFET on the surface move, they suffer serious distribution and reduce their mobility which leads to a reduction in the transconductance. But in the MESFET, the channel is formed at the bottom of the active layer and the carrier mobility is less affected. For this reason, the MESFETs are faster than the MOSFETs. The MESFET has important features such as higher speed, more power, lower noise and the possibility of their use of higher frequency, so we can use it in high voltage, high power, high frequency and low noise applications. Also, using appropriate materials as the substrate has an important role in the performance of MESFETs. Silicon carbide (SiC) material has important features such as wider bandgap, smaller size and lower weight compared to Si and GaAs, and this material is developed as a third material after Si and GaAs (Sghaier et al., 2003). Therefore, SiC MESFETs can be a good candidate for high power, high voltage, high power and high temperature applications due to the superior SiC material properties, specifically including high critical electric field, high electron saturation velocity and high thermal conductivity (Deng et al., 2008; Hjelmgren, Allerstam, Andersson, Nilsson, & Rorman, 2010; Rusli Zhu, Zhao, & Xia, 2006; Sriram et al., 2009; Zhang et al., 2008; Zhu, Rusli, & Zhao, 2007). Various approaches have been proposed to improve DC and radio frequency (RF) characteristics of MESFETs (Aminbeidokhti & Orouji, 2013; Elahipanah, 2010; Jia, Yang, & Zhang, 2013; Jia, Zhang, Xing, & Ma, 2015; Orouji, Aminbeidokhti, & Rahimian, 2011; Orouji, Khayatian, & Keshavarzi, 2016; Orouji, Roustaie, & Ramezani, 2016; Ramezani, Orouji, & Agharezaei, 2016; Ramezani, Orouji, & Keshvarzi, 2014; Razavi, Zahiri, & Hosseini, 2013; Roustaie & Orouji, 2017; Ueno, Urushidani, Hashimoto, & Seki, 1995).